1. Field of the Invention
The present invention relates to an image forming apparatus, and, in particular, to an image forming apparatus used in, for example, a copier, a printer, a facsimile machine, a composite machine or such, and carrying out image forming by jetting recording liquid such as ink on a recording medium such as recording paper.
2. Description of the Related Art
An ink jet recording apparatus used as one of various types of image forming apparatuses such as a printer, a facsimile machine, a copier, a plotter or such includes a serial-type image forming apparatus which has a liquid jetting head (recording head) which jets recording liquid (for example, ink) via microscopic nozzles mounted on a carriage, moves the carriage in a main scanning direction and forms (records) an image on a recording medium (which may be simply referred to as ‘sheet’ hereinafter, and for which, material thereof is not limited to paper, and the term ‘recording medium’ is used here to mean even various types of sheets called recording paper, transfer paper, a recording medium or such) with the recording head.
A non-impact recording method is advantageous in terms of a noiseless method in which, even at a time of recording, noise is so small that it may be ignored. Especially, an ink jet recording method is very advantageous recording method in which printing can be carried out at a high speed, and also, printing can be carried out even on a so-called ordinary paper without requiring any special recording liquid (or ink) fixing treatment. Further, for the ink jet recording method, various types of color recording methods employing color ink have been proposed and improved recently.
According to the ink jet recording method, a plurality of colors of ink droplets are made to fly, to be made to adhere to recording paper so as to carry out recording. For this purpose, an ink jet head is used.
Japanese Laid-open Patent Application No. 8-110660 discloses an image forming apparatus having such a type of an ink jet head, for example. This image forming apparatus is roughly shown in FIG. 9. As shown, the image forming apparatus 1 includes a paper supply cassette 3 provided in a bottom part of a body 2 and holding recording paper, a paper supply roller 4 which separates one sheet from the recording paper stored in the paper supply cassette 3 and supplies it, conveying rollers 5 conveying the sheet supplied by the paper supply roller 4, a conveying roller 7 which reverses the paper sheet conveyed by the conveying rollers 5 and supplies it to an ink jet head 6, and ejecting rollers 9 which eject the recording paper on which printing is carried out with the ink jet head 6 to a pressing plate 8 provided at a top part of the body 2.
In this image forming apparatus 1, the ink jet head 6 is disposed above a printing side of the recording paper, jets ink on the recording paper with the use of gravity force naturally applied to the ink itself, and thus, prints on the top side of the recording paper.
However, in the image forming apparatus 1 in the related art, since the ink jet head 6 is disposed above the recording side of the recording paper, and carries out printing on the top side of the recording paper which is then ejected on the pressing plate 8, a subsequent recording paper sheet on which printing is subsequently carried out is ejected on the printed side the recording paper sheet on which printing has been previously carried out. As a result, it is not possible to keep the original page order of the recording paper sheets. Accordingly, it is necessary to correct the page order of the recording paper sheets after the printing thereon by means of the image forming apparatus 1 is finished for all the pages.